Modular conveyor unit

ABSTRACT

A modular conveyor unit wherein the powered means includes endless chains arranged in pairs, one pair being normal to the other, with the chains of each pair offset lengthwise with respect to each other so that the end of one chain is immediately adjacent one edge of the unit and the other is adjacent the other and the opposite end of each chain is spaced sufficiently from the opposite edge of the unit to permit a chain of the pair normal there to pass between it and the adjacent side of the unit.

United States Patent Norman M. Sullivan;

Francis J. Fitzgerald, both of Grand Rapids, Mich.

Apr. 11, 1969 July 13, 1971 Rapistan Incorporated Grand Rapids, Mich.

Inventors Appl. No. Filed Patented Assignee MODULAR CONVEYOR UNIT 15 Claims, 6 Drawing Figs.

U.S.Cl 198/311, 198/20 1m. Cl 865g 47/26 FleldoiSearch 198/20,31

[56] References Cited UNITED STATES PATENTS 2,254,290 9/1941 Joa 198/20 Primary Examiner-Richard E. Aegerter Anarneylrice, Henefl eld, Huizenga & Cooper PATENIED JUL I 3 ISII L3, 597. 3 2 if SHEET 1 [IF 3 o I I a N h} IGHZ ,J INVENTORS NORMAN M SULLIVAN FRANCIS J, FITZGERALD ATTORNEYS PATENTEU JUL 1 3 l9?! SHEET 2 [IF 3 m wvbl m INVENTORS NORMAN M. SULLIVAN FRANCIS J.FITZGERALD BY ATTORNEYS MODULAR CONVEYOR UNIT BACKGROUND OF THE INVENTION This application is related to and is an extension of our earlier filed application Ser. No. 703,514, which has an assignec common to the instant application. As in the earlier application, the problem to be solved is to provide a standardized, modular, conveyor unit which will allow a conveyor system to be reorganized and rearranged, utilizing the same units without reengineering the entire system. The instant application has an advantage over the aforesaid earlier filed application, in that the powered means are so arranged that when a load moves on any one of the conveyor units in one of the two directions of which the powered means of the unit is capable, the load, irrespectiveof the direction of movement, will be driven at all times by the powered means while it is being transferred to an adjacent modular unit.

SUMMARY OF THE INVENTION This invention provides an improved modular conveyor unit comprising a frame having four sides, a load-supporting bed positioned upon and affixed to the frame and having a series of means rotatably mounted thereon for supporting the load while permitting selective movement thereof in a plane generally parallel to the bed; a first powered means positioned within the bed parallel to two of the sides for moving the load selectively in either of two opposite directions; a second powered means positioned parallel to the other two sides for moving the load in a direction transverse to the aforesaid directions, each of the powered means being a pair of propelling members and having an independent power source; and means for raising and lowering each of said powered means alternately; wherein the improvement comprises the positioning of each of the propelling members so that each has one end extending to an edge of one of the sides of the unit and each of the four edges of said unit has an end of one propelling member extending thereto.

Accordingly, it is an object of this invention to provide an improved modular conveyor unit which will insure that loads are easily and positively transferred to the next adjacent modular unit.

It is a further object of the invention to provide a modular conveyor unit of the above character wherein the powered means are so positioned that when operated in pairs, one of them will carry a load to the edge of the unit while applying driving force to the load at all times to assure positive transfer from one unit to the other.

Other objects and advantages of the invention will become apparent upon reference to the following drawings and detailed discussion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective view of the improved modular conveyor unit utilizing our invention, illustrating the outline of adjacent units;

FIG. 2 is a cross-sectional view taken along plane ll-II of FIG. 1;

FIG. 3 is a cross-sectional view taken along plane III-III of FIG. 1;

FIG. 4 is a diagrammatic plan view of the unit illustrated in FIG. 1;

FIG. 5 is a fragmentary sectional view taken along the line V-V of FIG. 3; and

cept disclosed in our aforesaid copending application. As'in the aforesaid application, the unit comprises a frame 10 having four sides I1, 11a, 12 and 12a adjacent to which identical modular units are positioned so as to convey the load in the manner and sequence as disclosed in the aforesaid application. Welded to the frame is a bed 13 having mounted thereon a large number of casters 14 to support the load so conveyed. To permit the load to have selective movement over the casters, the casters are pivotably mounted for rotation about a vertical axis to permit them to adjust their position to facilitate the movement of the load in any one of four directions. Such an arrangement is conventional. Thus, the casters will all be oriented in one of the four linear directions in which the modular unit is capable of operating, which in FIG. I is illustrated as being from right to left.

To drive the load over the bed formed by the casters 46, two pairs of endless chains and 20a and 21 and 21a each having load driving pads 22 attached to the links at periodic intervals are utilized. Each chain is mounted on sprockets similar to the sprockets 24 and 25 illustrated in FIG. 2 for the chain 21a. The chain pair 20 and 20a is positioned adjacent to the parallel to sides 11 and 11a and the chair pair 21 and 21a is positioned adjacent to the sides 12 and 12a respectively. Thus, the chain pairs are perpendicular to each other. The chains of each pair are synchronously driven and are reversible, so that together the two pairs provide the four directions in which the load is to move over the bed. The sprockets 24 for each pair of chains are mounted on a shaft 26 and the sprockets 25 for the same pair of chains are mounted on a shaft 27. The shafts 26 and 27 are rotatably supported within the frame and are driven by means hereinafter explained.

To raise and lower each of the pairs of endless chains 20 and 20a and 21 and 21a alternately so that only one pair is operatively connected to a load at any one time, each of the chains is supported between the sprockets by an elongated shoe 30 connected to stationary members 32 forming part of the frame 10 by guide links 34. The shoes 30 are actuated by a lift linkage 36 which is rotatably powered by means of an elongated shaft 37, connecting the two shoes 30 which support each of the two chains forming one of the two pairs. The shaft 37 is rotated by means of a crank 38 nonrotatably affixed thereto. The crank 38 is actuated by means of an air cylinder 39 mounted to the frame as indicated in FIG. 2. The lower run of the chain forming the powered means is supported within a suitable chain return track 40. It will be noted that the shoe 30 normally supports the chain comprising the powered means below the level of the bed formed by the casters 14, as illustrated in FIG. 2. When the links 34 rotate upwardly by the action of the linkage 36 being rotated by the crank 38, the chain then occupies a position of frictional engagement with the bed formed by the casters 14 so as to grip the load and propel it over the casters. Inasmuch as each pair of chains forming a powered means is lifted by the rotation of the same shaft 37, the pair of chains will act together in being lifted into or being lowered out of engagement with the load. The chains do not support the load, this function remaining with the casters. The

upward pressure exerted by the pads on the load is only sufficomprising theinvention has a four-sided symmetry. Thus, a

FIG. 6 is a fragmentary diagrammatic plan view illustrating I another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT single shaft is rotated by a crank powered by an air cylinder, the single shaft causing two lift shoes to lift the two chains 20 and 20a into engagement with the load, this being done of course when the powered means formed by the chains 21 and 21a are out of engagement.

In accordance with our improvement with our improvement constituting the invention, the endless chains forming the two powered means-have been repositioned within the bed'in the following manner. The sprocket'25 mounting each'ofthe' endless chains forming the powered means is positioned at the edge of the bed, while the sprocket 24 mounting the endless chain at the other end of the powered means is not so positioned, so that each endless chain has an operating end ex tending to an edge of the unit and each of the four edges of the unit has extending to it an operating end of one of the chains forming the powered means. Thus, the end of the chain 21a as represented by the position of the sprocket 25, extends to the edge of the frame 110 while the end of that chain 21a as represented by the position of the sprocket 24 does not. The same is true for each of the other chains, for example, the chain 21 has its end represented by sprocket 25 extending to the edge 11 of the unit and the chain 20 has its end represented by sprockets 25 extending to the edge 12a of the unit. By this construction, the propelling member formed by each endless chain extends its full length without being interrupted by the presence of another propelling member.

In accordance with another aspect of our invention, the endless chains which are parallel and operate as a pair, for example, chains 21 and Zia, are driven by a common drive shaft 41 and by chain means driving the shafts 26 and 27 upon which the sprockets 24 ax... 25 are mounted. To connect the drive shaft 41 to the shafts 26 and 2'7, a sprocket 42 is mounted on the drive shaft 41 and an endless chain 43 is powered by that sprocket and is mounted over end sprockets 44 which are affixed to the shafts 26 and 27. it will be apparent from reference to FlG. i that each of the chains 43 is parallel and adjacent to the chain comprising the powered means driven by that chain 43. Thus, the rotation of the sprocket 42 forces the chain 43 to operate the sprockets 44 and thereby the shafts 26 and 27 which in turn drive the endless chains 21 and 21a forming one pair of the powered means. The drive shaft il is in turn actuated and driven by means of a small sprocket 48 mounted thereon, the sprocket 48 being driven by a chain 49 operated by a motor 54 The end of the shaft 41 opposite to that illustrated in H6. 3 has an identical sprocket 42 mounted thereon to drive the identical chain 43 so as to power the other propelling member chain 21a, of the pair. The purpose of driving the chains 21 and 21a from both ends is to eliminate the takeup of slack in the chain in the top run where it would result in erratic or jarring movement of the load when operation is initiated. This is particularly important in this type of equipment since it is designed to handle unit loads which may weigh several tons.

The preceding discussion illustrates the means for driving the chains 21 and 21a which operate as a pair to form one of the powered means which moves a load. A similar construction is provided to drive the chains 20 and 20a which operate as a pair to form the other powered means, the only difference being the location of the motor and the drive shaft which provide the power to the two chains 20 and 200. Thus, a motor 56 operates to drive a pair of chains 57 mounted over end sprockets 58, the latter of which are similar to the sprockets 44 operating the chains 21 and 21a. The chains 57 are positioned generally at the same height, parallel to and adjacent to the chains 20 and 20a, the end sprockets i driven by the chain 57 being mounted on the shafts 26 and 27 so as to actuate the sprockets 24 and 25, respectively, so as to move those chains and 20a. The main difference in the construction of the drive train for the chains 20 and 20a is the positioning of the drive shaft 59 below the position of the drive shaft 4i utilized for the other pair of chains (FIG. 3 and 4). The drive shaft 59 is driven by a small sprocket 48 operated by a chain 49 as in the case of the power train for the other two chains 21 and 21a, except that the motor 56 drives the chain 49 from a different position in the bed. Also, because the drive shaft 5Q is below the shaft 411, an oversized sprocket so (HO. 5) is mounted on the drive shaft 59 so as to engage and drive the chains 57 operating the pairs of chain 20 and 20a constituting the second powered means. Because the sprocket 60 is oversized, the chain 57 on its return below the bed 23 drops from the point where it leaves the end sprocket until it reaches the bottom of the driving sprocket 60. To compensate for the use of the larger sprocket so. the sprocket size ratio between the motor 56 and the shaft 59 is different from that between the motor 54 and the shaft 4i so that all chains in the conveyor unit have the same lineal speed. it will be recognized that numerous other mechanical arrangements could be utilized to accomplish the same result.

FIG. (5 illustrates an alternate embodiment of the invention, wherein the powered means actually extends to the edge of the unit. The parts in this embodiment which correspond to those previously described have the same reference numerals to which the distinguishing number MN) has been added. Thus, the endless chain HZti-n projects out to the edge ll 12 of the unit, as does the chain 157 which drives the chain 112% by the same means as expiained above. This embodiment is in contrast with the previous embodiment, inasmuch as the previous one does not provide chains extending to the edge ofthe unit.

It will be seen that either embodiment of this invention provides positive drive or propulsion to the load in all four directions entirely across the conveyor unit. Thus, the necessity for auxiliary drives to receive a ioad and move it to receive a load and move it to engage the chains or to complete its discharge is eliminated. This significantly reduces the cost and complexity of the unit. it also permits the units to operate effectively with loads oi reduced length in the direction of movement because the gap between the effective ends of the chains of two adjacent units is reduced.

The fact that only one chain is driving the load for a short distance adjacent each edge has been found to be quite satisfactory despite the eccentric application of force to the load. Until the edge of the load has been released by the shorter of the chains, it is symmetrically driven and before the release occurs the forward end of the load has been engaged by the first chain of the next unit. Since these chains will be on opposite sides of the load, symmetry of drive will again be established keeping the load moving forward in a straight path.

it will be recognized that if a load is to be redirected at one of the units, it is first moved onto and centered on the unit by one set of chains. These chains will then be lowered to disengage and the other set raised to drive the load at a right angle to its original direction of movement.

While the invention has been described in connection with the preferred embodiment, it wiil be understood that it will not be limited to that described. To the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the following claims.

The embodiments ofthe invention in which we claim an exclusive property or privilege are defined as follows:

i. A modular conveyor unit for a load transport system having a four-sided frame, first powered means for moving a load over said unit, second powered means for moving a load over said unit in a direction normal to that of said first powered means, and a power source to drive said first and second powered means independently of each other, each of said powered means including a pair of spaced, elongated propelling members extending generally parallel to one another and to one of the sides of said frame, means for raising and lowering said first and second powered means alternatively whereby only one of them is operatively engaged to a load at any one time, said conveyor unit characterized in that each propelling member has one end extending closer to one edge of said unit than to the edge opposite from said one edge thereof and each of the four edges of said unit has an end of .one propelling member extending substantially thereto whereby loads can be forcibly moved across said unit in either of two linear paths normal to each other from the edge of entry to the edge of discharge.

2. The modular conveyor unit as defined in claim 1 wherein the extension of each propelling member is uninterrupted by the presence of another propelling member.

3. The modular conveyor unit as defined in claim 2 wherein said propelling member includes an endless chain having load gripping members on the periphery thereof.

4, The modular conveyor unit as defined in claim 1 wherein a pair of said propelling members is driven from a common drive shaft.

5. The modular conveyor unit as defined in claim 4 wherein each of said members driven as a pair is driven at both ends from a common power source.

6. The modular conveyor unit as defined in claim I wherein each one propelling member extends to the plane of said edge of said unit.

7. The unit as set forth in claim 1 which further comprises means on said unit for movably supporting a load positioned thereon.

8. The unit as set fourth in claim 1 wherein said power source is reversible such that at least one pair of said propelling members can be driven in either of two opposite directions.

9. A modular conveyor unit for a load transport system having a four-sided frame, first powered means for moving a load over said unit in a first direction, second powered means for moving a load over said unit in a direction transverse to said first direction, and a power source to drive said first and second powered means independently of each other, each of said powered means including a pair of spaced, endless chains extending adjacent and generally parallel to opposite sides of said frame, the extension of each of said chains being uninterrupted by the presence of another chain; means for raising and lowering said first and second power means alternatively whereby only one of them is operatively engaged to a load at any one time, said conveyor unit characterized in that one chain of each of said powered means extends substantially to oneedge of saidframe and the other chain of each of said powered means extends substantially to an edge of said frame opposite from said one edge, whereby loads can be forcibly moved across said unit in any of four directions from the edge of entry to the edge of discharge.

10. The modular conveyor unit as defined in claim 9 wherein each of said chains extends closer to said one edge than it does to the edge of said frame opposite from said one edge.

11. The modular conveyor unit as defined in claim 10 wherein a pair of said chains is driven from a common drive shaft.

12. The modular conveyor unit as defined in claim 11 wherein each said pair is driven by a pair of driving chains mounted over two sprockets connected to a common drive shaft, said drive shaft for one of said powered means being positioned below said shaft for said other powered means.

13. The modular conveyor unit as defined in claim 9 wherein said one chain ofeach of said powered means extends to the plane of said edge ofsaid unit.

14. The unit as set forth in claim 9 which further comprises means on said unit for movably supporting a load positioned thereon.

15. The unit as set forth in claim 9 wherein said power source is reversible such that at least one pair of said chains can be driven in either of two opposite directions.

w g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, Dated 13,

Inventor(s) Norman M. Sullivan 3 Francis J. Fitzgerald It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 2;

"a pair" should be each pair Column 5, line 8;

"each one" should be each said Column 5 line 8;

"said edge" should be one edge Column 6, line 12;

"a pair" should be each pair Column 6, line 22;

"said edge" should be one edge Signed and sealed this L th day of July 1972.

(SEAL) Attest:

ILDZ'JARD I-LFLLTCHER, JR. R0 ERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. A modular conveyor unit for a load transport system having a four-sided frame, first powered means for moving a load over said unit, second powered means for moving a load over said unit in a direction normal to that of said first powered means, and a power source to drive said first and second powered means independently of each other, each of said powered means including a pair of spaced, elongated propelling members extending generally parallel to one another and to one of the sides of said frame, means for raising and lowering said first and second powered means alternatively whereby only one of them is operatively engaged to a load at any one time, said conveyor unit characterized in that each propelling member has one end extending closer to one edge of said unit than to the edge opposite from said one edge thereof and each of the four edges of said unit has an end of one propelling member extending substantially thereto whereby loads can be forcibly moved across said unit in either of two linear paths normal to each other from the edge of entry to the edge of discharge.
 2. The modular conveyor unit as defined in claim 1 wherein the extension of each propelling member is uninterrupted by the presence of another propelling member.
 3. The modular conveyor unit as defined in claim 2 wherein said propelling member includes an endless chain having load gripping members on the periphery thereof.
 4. The modular conveyor unit as defined in claim 1 wherein a pair of said propelling members is driven from a common drive shaft.
 5. The modular conveyor unit as defined in claim 4 wherein each of said members driven as a pair is driven at both ends from a common power source.
 6. The modular conveyor unit as defined in claim 1 wherein each one propelling member extends to the plane of said edge of said unit.
 7. The unit as set forth in claim 1 which further comprises means on said unit for movably supporting a load positioned thereon.
 8. The unit as set fourth in claim 1 wherein said power source is reversible such that at least one pair of said propelling members can be driven in either of two opposite directions.
 9. A modular conveyor unit for a load transport system having a four-sided frame, first powered means for moving a load over said unit in a first direction, second powered means for moving a load over said unit in a direction transverse to said first direction, and a power source to drive said first and second powered means independently of each other, each of said powered means including a pair of spaced, endless chains extending adjacent and generally parallel to opposite sides of said frame, the extension of each of said chains being uninterrupted by the presence of another chain; means for raising and lowering said first and second power means alternatively whereby only one of them is operatively engaged to a load at any one time, said conveyor unit characterized in that one chain of each of said powered means extends substantially to one edge of said frame and the other chain of each of said powered means extends substantially to an edge of said frame opposite from said one edge, whereby loads can be forcibly moved across said unit in any of four directions from the edge of entry to the edge of discharge.
 10. The modular conveyor unit as defined in claim 9 wherein each of said chains extends closer to said one edge than it does to the edge of said frame opposite from said one edge.
 11. The modular conveyor unit as defined in claim 10 wherein a pair of said chains is driven from a common drive shaft.
 12. The modular conveyor unit as defined in claim 11 wherein each said pair is driven by a pair of driving chains mounted over two sprockets connected to a common drive shaft, said drive shaft for one of Said powered means being positioned below said shaft for said other powered means.
 13. The modular conveyor unit as defined in claim 9 wherein said one chain of each of said powered means extends to the plane of said edge of said unit.
 14. The unit as set forth in claim 9 which further comprises means on said unit for movably supporting a load positioned thereon.
 15. The unit as set forth in claim 9 wherein said power source is reversible such that at least one pair of said chains can be driven in either of two opposite directions. 